Outdoor luminaires require both continuous and effective seals for the internal electronics as well as easy access for maintenance purposes, two goals which are often at odds with each other. This is particularly of import when considering the environmental conditions which outdoor lighting operates. Most systems have attempted to accomplish such with permanent seals positioned around the lens so that these seals are never breached during the life of the luminaire. Other luminaire housings have included various hinged lens frame structures which require removable screws be utilized. However, use of such technology often requires tapping holes into the housing which extend around the perimeter of the lens and the areas to be sealed. Such structure requires additional assembly and manufacturing steps as well as causes potential breach areas for moisture and other dirt to intrude into the interior of the housing. Such moisture, dust, dirt and foreign substance intrusion reduces the life expectancy of the luminaire, changes the overall light output and footprint of the lamps and possibly can foul the electronics. Further, maintenance using removable screws around the perimeter of the lens can increase the difficulty in maintenance by requiring personnel to remove the threads with tools and typically in a high position in a bucket.
Further, such affixation structures can also pinch or provide improper pressure on the seals positioned between the lens frame and the housing. Such structure requires direct alignment of the lower and upper frame portions so that the tap holes allow for the screws to be threaded readily therethrough. After significant use or after repeated heating and cooling cycles, misalignment can result thereby making maintenance and reassembly that much more difficult.
With new LED technology, the requirement for large voluminous interior cavities for outdoor light fixture heat dissipation is additionally reduced. Therefore, direct threading by bolts or screws of a lower lens frame over an LED panel or light engine requires unneeded housing structure which also interferes with the cooling characteristics of the LEDs or of the head sink. Such direct affixation can further cause transference of the heat energy from the main housing or heat sink directly to the lens.